Singer, Bradley S. Temporal evolution of arc magmatism and hydrothermal activity, including epithermal gold veins, Borovitsa Caldera, southern Bulgaria - Lancaster, PA Economic Geology Publishing Company August 2000 - pp. 1155-1164 ilus., tbls. Subjects--Topical Terms: ALTERACIÓN HIDROTERMALDATACION AR-ARGEOLOGIA ECONOMICAMAGMATISMOMINERALIZACIONSISTEMAS GEOTERMICOSYACIMIENTOS EPITERMALES Subjects--Geographic Terms: BULGARIA